"1 And the Lord visited Sarah as he had said, and the Lord did unto Sarah as he had spoken.

2 For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him.

3 And Abraham called the name of his son that was born unto him, whom Sarah bare to him, Isaac.

4 And Abraham circumcised his son Isaac being eight days old, as God had commanded him.

5 And Abraham was an hundred years old, when his son Isaac was born unto him.

6 And Sarah said, God hath made me to laugh, so that all that hear will laugh with me.

7 And she said, Who would have said unto Abraham, that Sarah should have given children suck? for I have born him a son in his old age.

8 And the child grew, and was weaned: and Abraham made a great feast the same day that Isaac was weaned.

9 And Sarah saw the son of Hagar the Egyptian, which she had born unto Abraham, mocking.

10 Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac.

11 And the thing was very grievous in Abraham's sight because of his son.

12 And God said unto Abraham, Let it not be grievous in thy sight because of the lad, and because of thy bondwoman; in all that Sarah hath said unto thee, hearken unto her voice; for in Isaac shall thy seed be called.

13 And also of the son of the bondwoman will I make a nation, because he is thy seed." - Genesis 21:1-13

Here we read in Genesis chapter 21 of the fulfilling of God's promise to Abraham and Sarah. God finally gave them their promised son, Isaac. It was a miracle. Abraham and Sarah were, by today's standard, far too old to have children. And yet, God was still able to cause them to conceive and give birth. It was truly a miracle.

But in the midst of all this joy, we see a major conflict arise. Ishmael, the son of Hagar, began to mock the child Isaac, when he was fully weaned.

Verse 9 says, "And Sarah saw the son of Hagar the Egyptian, which she had born unto Abraham, mocking." - Genesis 17:9

At this point in time, we conclude that Ishmael was approximately 14 or 15 years of age by now (see Genesis ch. 17:25). The 14 year old Ishmael was making fun of the very young Isaac, who was perhaps only about 2 years old.

But notice what Sarah's response was to this young teenager's bad behavior.

Verse 10 says, "Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac." - Genesis 17:10

We see this verse from Genesis is repeated by the apostle Paul in his epistle to the Galatians.

"28 Now we, brethren, as Isaac was, are the children of promise.

29 But as then he that was born after the flesh persecuted him that was born after the Spirit, even so it is now.

30 Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman.

31 So then, brethren, we are not children of the bondwoman, but of the free." - Galatians 4:28-31

The allegory that Paul was trying to derive from this old story from Genesis, is that those who have not been born of the Spirit shall be "cast out" into outer darkness, that is, hell. Also, notice that Paul says that, "Now we, brethren, as Isaac was, are the children of promise." - vs. 28.

The children of promise are those who have been born again. Those who have believed on the Lord Jesus Christ for salvation. These are the children of promise.

And what is the promise?

1 John 2:25 says, "And this is the promise that he hath promised us, even eternal life."

God made a promise to humanity long ago that he would grant eternal life to anyone who would receive Jesus Christ as his Lord and Saviour.

Titus 1:1-2 says, "Paul, a servant of God, and an apostle of Jesus Christ, according to the faith of God's elect, and the acknowledging of the truth which is after godliness; In hope of eternal life, which God, that cannot lie, promised before the world began."

The Bible says that God, that cannot lie, promised us eternal life before the world began.

But notice that the scripture says, "Cast out the bondwoman and her son." - Galatians 4:30.

The complete opposite is true for those who have rejected God. Those who have hated Jesus Christ, and those who mock him, as Ishmael did, will be cast out. They will not partake of the inheritance which those blessed children of God will enjoy. They will be cast out.

You must realize that this scripture paints a picture of the lost individual. The lost person is a son of bondage, and this bondage is sin. The sons of bondage are unbelievers. They were born into this bondage, and no one can set them free except the Master. Only Jesus can set them free, because he said, "Verily, verily, I say unto you, Whosoever committeth sin is the servant of sin. And the servant abideth not in the house for ever: but the Son abideth ever. If the Son therefore shall make you free, ye shall be free indeed." - John 8:34-36

The sons of bondage are not only born into the bondage of sin, but they are children of the one who has put them into bonds, that is, the devil.

"8 He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.

9 Whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin, because he is born of God.

10 In this the children of God are manifest, and the children of the devil: whosoever doeth not righteousness is not of God, neither he that loveth not his brother." - 1 John 3:8-10

It is when the lost person believes on Jesus Christ for salvation that he becomes born again. This new birth ensures that he is given a new Father, which is God. No longer is he a child of bondage. No longer is he a son of Hagar, but now he is a child of the freewoman, of Jesus Christ. As Isaac was born as the child of promise, so too must sons be born into the family of God through faith in the Lord Jesus Christ. One must call upon his name and receive the gift of eternal through Jesus Christ our Lord.

Friend, if you are not sure of your proper birth. If you are uncertain about who your mother is. If your mother is Hagar, and if you are a child of the devil, then may I advise you to give your heart to Jesus. Become born again. Let Jesus come into your heart, and let him take up his proper throne inside. Jesus said in Revelation 3:20, "Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me."

Will you let him in? Will you receive him? Or will you let him stay out in the cold and in the rain? Have you any room for Jesus?

Believe on Jesus Christ. Receive him. Be saved. Be born again. Become a son of the promise.